/* 全局样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* 根变量定义 */
:root {
    /* 颜色系统 - 基于主站但优化为学习主题 */
    --primary-dark: #1a2f1a;
    --primary-green: #2d5a3d;
    --accent-gold: #d4af37;
    --accent-sage: #9cae9c;
    --accent-blue: #4a90e2;
    --accent-purple: #8e4ec6;
    --text-light: #f5f5f5;
    --text-muted: #a8b8a8;
    --text-accent: #e8f4f8;
    --bg-dark: #0f1610;
    --bg-section: #1a2019;
    --bg-card: rgba(45, 90, 61, 0.1);
    --bg-feature: rgba(212, 175, 55, 0.05);
    
    /* 字体 */
    --font-serif: 'Noto Serif SC', 'Playfair Display', serif;
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'Fira Code', 'Monaco', monospace;
    
    /* 间距 */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    
    /* 动画 */
    --transition-smooth: all 0.4s cubic-bezier(0.25, 0.8, 0.25, 1);
    --transition-gentle: all 0.6s cubic-bezier(0.23, 1, 0.32, 1);
    --transition-bounce: all 0.5s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

/* 基础样式 */
html {
    scroll-behavior: smooth;
    font-size: 16px;
}

body {
    font-family: var(--font-sans);
    background: linear-gradient(135deg, var(--bg-dark) 0%, var(--primary-dark) 100%);
    color: var(--text-light);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* 导航栏 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(15, 22, 16, 0.95);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(212, 175, 55, 0.1);
    z-index: 1000;
    transition: var(--transition-smooth);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.logo-main {
    font-size: 1.8rem;
    font-weight: 600;
    color: var(--accent-gold);
    font-family: var(--font-sans);
    letter-spacing: -0.02em;
}

.logo-sub {
    font-size: 1rem;
    font-weight: 300;
    color: var(--text-muted);
    font-family: var(--font-serif);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-lg);
}

.nav-menu a {
    color: var(--text-light);
    text-decoration: none;
    font-weight: 400;
    font-size: 0.95rem;
    transition: var(--transition-smooth);
    position: relative;
}

.nav-menu a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-gold);
    transition: var(--transition-smooth);
}

.nav-menu a:hover {
    color: var(--accent-gold);
}

.nav-menu a:hover::after {
    width: 100%;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 4px;
}

.nav-toggle span {
    width: 25px;
    height: 2px;
    background: var(--text-light);
    transition: var(--transition-smooth);
}

/* 英雄区域 */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    padding: var(--spacing-xl) 0;
    background: radial-gradient(circle at 30% 50%, rgba(212, 175, 55, 0.1) 0%, transparent 50%),
                radial-gradient(circle at 70% 80%, rgba(74, 144, 226, 0.08) 0%, transparent 50%);
}

.hero-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    align-items: center;
    z-index: 2;
    position: relative;
}

.hero-title {
    font-size: 4rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    line-height: 1.1;
}

.title-main {
    color: var(--accent-gold);
    font-family: var(--font-sans);
    display: block;
    font-size: 4.5rem;
    letter-spacing: -0.03em;
}

.title-divider {
    color: var(--accent-sage);
    font-weight: 300;
    margin: 0 var(--spacing-xs);
}

.title-sub {
    color: var(--text-light);
    font-family: var(--font-serif);
    font-size: 2rem;
    font-weight: 300;
    display: block;
    margin-top: var(--spacing-xs);
}

.hero-subtitle {
    font-size: 1.4rem;
    color: var(--text-accent);
    margin-bottom: var(--spacing-md);
    font-weight: 400;
}

.hero-description {
    margin-bottom: var(--spacing-lg);
}

.hero-description p {
    font-size: 1.1rem;
    color: var(--text-muted);
    line-height: 1.7;
}

.hero-actions {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.btn-primary, .btn-secondary {
    padding: var(--spacing-sm) var(--spacing-lg);
    border: none;
    border-radius: 50px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition-smooth);
    font-family: var(--font-sans);
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent-gold) 0%, #f4d03f 100%);
    color: var(--primary-dark);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(212, 175, 55, 0.3);
}

.btn-secondary {
    background: transparent;
    color: var(--text-light);
    border: 2px solid var(--accent-sage);
}

.btn-secondary:hover {
    background: var(--accent-sage);
    color: var(--primary-dark);
    transform: translateY(-2px);
}

/* 学习演示卡片 */
.hero-visual {
    display: flex;
    justify-content: center;
    align-items: center;
}

.word-card {
    background: rgba(45, 90, 61, 0.15);
    border: 1px solid rgba(212, 175, 55, 0.2);
    border-radius: 20px;
    padding: var(--spacing-lg);
    backdrop-filter: blur(20px);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    transform: rotate(-5deg);
    transition: var(--transition-gentle);
    max-width: 350px;
}

.word-card:hover {
    transform: rotate(0deg) scale(1.05);
}

.word-main {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--accent-gold);
    text-align: center;
    margin-bottom: var(--spacing-xs);
    font-family: var(--font-sans);
}

.word-phonetic {
    font-size: 1.1rem;
    color: var(--accent-blue);
    text-align: center;
    margin-bottom: var(--spacing-sm);
    font-family: var(--font-mono);
}

.word-meaning {
    font-size: 1.2rem;
    color: var(--text-light);
    text-align: center;
    margin-bottom: var(--spacing-md);
    font-family: var(--font-serif);
}

.ai-insight {
    background: rgba(74, 144, 226, 0.1);
    border-left: 3px solid var(--accent-blue);
    padding: var(--spacing-sm);
    border-radius: 8px;
}

.ai-tag {
    display: inline-block;
    background: var(--accent-blue);
    color: white;
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 0.8rem;
    font-weight: 500;
    margin-bottom: var(--spacing-xs);
}

.ai-insight p {
    color: var(--text-accent);
    font-style: italic;
    font-size: 0.95rem;
    line-height: 1.5;
}

/* 浮动单词 */
.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    overflow: hidden;
    z-index: 1;
}

.floating-words {
    position: absolute;
    width: 100%;
    height: 100%;
}

.floating-word {
    position: absolute;
    font-size: 1.5rem;
    font-weight: 300;
    color: rgba(212, 175, 55, 0.1);
    font-family: var(--font-sans);
    animation: float 8s infinite ease-in-out;
}

.word-1 {
    top: 20%;
    left: 10%;
    animation-delay: 0s;
}

.word-2 {
    top: 60%;
    right: 15%;
    animation-delay: 2s;
}

.word-3 {
    bottom: 30%;
    left: 20%;
    animation-delay: 4s;
}

.word-4 {
    top: 40%;
    right: 30%;
    animation-delay: 6s;
}

@keyframes float {
    0%, 100% { transform: translateY(0px) rotate(0deg); opacity: 0.3; }
    50% { transform: translateY(-20px) rotate(5deg); opacity: 0.6; }
}

/* 通用部分样式 */
.section-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.section-title {
    font-size: 2.5rem;
    font-weight: 600;
    color: var(--text-light);
    margin-bottom: var(--spacing-md);
    font-family: var(--font-serif);
}

.section-divider {
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--accent-gold) 0%, var(--accent-sage) 100%);
    margin: 0 auto var(--spacing-md);
    border-radius: 2px;
}

.section-subtitle {
    font-size: 1.2rem;
    color: var(--text-muted);
    max-width: 600px;
    margin: 0 auto;
    line-height: 1.6;
}

/* 特色功能区域 */
.features {
    padding: var(--spacing-xl) 0;
    background: linear-gradient(180deg, transparent 0%, var(--bg-section) 100%);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.feature-card {
    background: var(--bg-feature);
    border: 1px solid rgba(212, 175, 55, 0.1);
    border-radius: 20px;
    padding: var(--spacing-lg);
    text-align: center;
    transition: var(--transition-gentle);
    backdrop-filter: blur(10px);
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 50px rgba(212, 175, 55, 0.1);
    border-color: rgba(212, 175, 55, 0.3);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-md);
    display: block;
}

.feature-card h3 {
    font-size: 1.4rem;
    color: var(--accent-gold);
    margin-bottom: var(--spacing-sm);
    font-family: var(--font-sans);
    font-weight: 600;
}

.feature-card p {
    color: var(--text-muted);
    line-height: 1.6;
}

/* 学习方式区域 */
.learning {
    padding: var(--spacing-xl) 0;
    background: var(--bg-section);
}

.learning-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    align-items: center;
}

.learning-methods {
    margin-top: var(--spacing-lg);
}

.method {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-md);
    border-radius: 15px;
    transition: var(--transition-smooth);
}

.method:hover {
    background: rgba(212, 175, 55, 0.05);
}

.method-number {
    min-width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--accent-gold) 0%, #f4d03f 100%);
    color: var(--primary-dark);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.2rem;
    font-family: var(--font-sans);
}

.method-content h3 {
    color: var(--accent-gold);
    font-size: 1.3rem;
    margin-bottom: var(--spacing-xs);
    font-family: var(--font-sans);
    font-weight: 600;
}

.method-content p {
    color: var(--text-muted);
    line-height: 1.6;
}

/* 思维导图可视化 */
.learning-visual {
    display: flex;
    justify-content: center;
    align-items: center;
}

.mind-map {
    position: relative;
    width: 400px;
    height: 400px;
}

.central-word {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: linear-gradient(135deg, var(--accent-gold) 0%, #f4d03f 100%);
    color: var(--primary-dark);
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: 50px;
    font-size: 1.3rem;
    font-weight: 600;
    font-family: var(--font-sans);
    box-shadow: 0 10px 30px rgba(212, 175, 55, 0.3);
    z-index: 10;
}

.branch {
    position: absolute;
    width: 120px;
}

.branch-1 { top: 10%; left: 50%; transform: translateX(-50%); }
.branch-2 { top: 50%; right: 10%; transform: translateY(-50%); }
.branch-3 { bottom: 10%; left: 50%; transform: translateX(-50%); }
.branch-4 { top: 50%; left: 10%; transform: translateY(-50%); }

.node {
    background: rgba(74, 144, 226, 0.2);
    color: var(--text-light);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: 25px;
    text-align: center;
    border: 1px solid var(--accent-blue);
    font-size: 0.9rem;
    font-weight: 500;
    animation: pulse 3s infinite ease-in-out;
}

.branch-1 .node { animation-delay: 0s; }
.branch-2 .node { animation-delay: 0.5s; }
.branch-3 .node { animation-delay: 1s; }
.branch-4 .node { animation-delay: 1.5s; }

@keyframes pulse {
    0%, 100% { transform: scale(1); opacity: 0.8; }
    50% { transform: scale(1.05); opacity: 1; }
}

/* AI 区域 */
.ai-section {
    padding: var(--spacing-xl) 0;
    background: linear-gradient(180deg, var(--bg-section) 0%, var(--bg-dark) 100%);
}

.ai-features {
    margin-top: var(--spacing-xl);
}

.ai-feature {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: var(--spacing-xl);
    align-items: center;
    margin-bottom: var(--spacing-xl);
    padding: var(--spacing-lg);
    border-radius: 20px;
    transition: var(--transition-smooth);
}

.ai-feature:nth-child(even) {
    grid-template-columns: 2fr 1fr;
}

.ai-feature:nth-child(even) .ai-feature-visual {
    order: 2;
}

.ai-feature:hover {
    background: rgba(74, 144, 226, 0.05);
}

.ai-feature-text h3 {
    color: var(--accent-gold);
    font-size: 1.4rem;
    margin-bottom: var(--spacing-sm);
    font-family: var(--font-sans);
    font-weight: 600;
}

.ai-feature-text p {
    color: var(--text-muted);
    line-height: 1.6;
    font-size: 1.1rem;
}

/* AI 可视化元素 */
.thinking-bubble {
    background: rgba(74, 144, 226, 0.1);
    border: 2px solid var(--accent-blue);
    border-radius: 30px;
    padding: var(--spacing-lg);
    position: relative;
    max-width: 250px;
    margin: 0 auto;
}

.thinking-bubble::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 30px;
    width: 20px;
    height: 20px;
    background: rgba(74, 144, 226, 0.1);
    border: 2px solid var(--accent-blue);
    border-radius: 50%;
    border-top-color: transparent;
    border-left-color: transparent;
}

.bubble-content {
    text-align: center;
}

.bubble-content span {
    font-size: 2rem;
    display: block;
    margin-bottom: var(--spacing-sm);
}

.bubble-content p {
    color: var(--text-light);
    font-size: 0.95rem;
    line-height: 1.4;
}

.connection-web {
    position: relative;
    width: 250px;
    height: 200px;
    margin: 0 auto;
}

.center-node {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: var(--accent-purple);
    color: white;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: 25px;
    font-weight: 600;
    z-index: 10;
}

.connected-node {
    position: absolute;
    background: rgba(212, 175, 55, 0.2);
    color: var(--accent-gold);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: 15px;
    font-size: 0.9rem;
    border: 1px solid var(--accent-gold);
}

.node-1 { top: 20%; left: 20%; }
.node-2 { top: 20%; right: 20%; }
.node-3 { bottom: 20%; left: 50%; transform: translateX(-50%); }

.connection {
    position: absolute;
    height: 2px;
    background: linear-gradient(90deg, var(--accent-purple) 0%, var(--accent-gold) 100%);
    opacity: 0.6;
}

.line-1 {
    top: 45%;
    left: 35%;
    width: 30%;
    transform: rotate(-30deg);
}

.line-2 {
    top: 45%;
    right: 35%;
    width: 30%;
    transform: rotate(30deg);
}

.line-3 {
    bottom: 35%;
    left: 50%;
    width: 25%;
    transform: translateX(-50%) rotate(90deg);
}

.growth-chart {
    display: flex;
    align-items: end;
    gap: var(--spacing-sm);
    height: 150px;
    width: 200px;
    margin: 0 auto;
    position: relative;
}

.chart-bar {
    background: linear-gradient(180deg, var(--accent-blue) 0%, var(--accent-purple) 100%);
    width: 30px;
    border-radius: 15px 15px 0 0;
    animation: grow 2s ease-out forwards;
}

.bar-1 { height: 60px; animation-delay: 0s; }
.bar-2 { height: 80px; animation-delay: 0.2s; }
.bar-3 { height: 100px; animation-delay: 0.4s; }
.bar-4 { height: 120px; animation-delay: 0.6s; }

@keyframes grow {
    from { height: 0; }
}

/* 联系区域 */
.contact {
    padding: var(--spacing-xl) 0;
    background: var(--bg-section);
}

.contact-content {
    margin-top: var(--spacing-xl);
}

.contact-info {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.contact-item {
    background: rgba(45, 90, 61, 0.1);
    padding: var(--spacing-lg);
    border-radius: 20px;
    border: 1px solid rgba(212, 175, 55, 0.1);
    text-align: center;
    transition: var(--transition-smooth);
}

.contact-item:hover {
    transform: translateY(-5px);
    border-color: rgba(212, 175, 55, 0.3);
}

.contact-item h3 {
    color: var(--accent-gold);
    font-size: 1.3rem;
    margin-bottom: var(--spacing-sm);
    font-family: var(--font-sans);
    font-weight: 600;
}

.contact-item p {
    color: var(--text-muted);
    margin-bottom: var(--spacing-md);
    line-height: 1.6;
}

.social-links {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
}

.social-link {
    padding: var(--spacing-xs) var(--spacing-md);
    background: transparent;
    border: 1px solid var(--accent-sage);
    color: var(--text-light);
    text-decoration: none;
    border-radius: 25px;
    transition: var(--transition-smooth);
    font-size: 0.9rem;
}

.social-link:hover {
    background: var(--accent-sage);
    color: var(--primary-dark);
}

.contact-email {
    color: var(--accent-blue);
    text-decoration: none;
    font-family: var(--font-mono);
    font-size: 0.95rem;
}

.contact-email:hover {
    color: var(--accent-gold);
}

/* 页脚 */
.footer {
    background: var(--bg-dark);
    padding: var(--spacing-xl) 0 var(--spacing-md);
    border-top: 1px solid rgba(212, 175, 55, 0.1);
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-lg);
}

.footer-brand {
    text-align: left;
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-sm);
}

.footer-logo .logo-main {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--accent-gold);
    font-family: var(--font-sans);
}

.footer-logo .logo-sub {
    font-size: 0.9rem;
    color: var(--text-muted);
    font-family: var(--font-serif);
}

.footer-tagline {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-lg);
}

.footer-section h4 {
    color: var(--accent-gold);
    font-size: 1.1rem;
    margin-bottom: var(--spacing-sm);
    font-family: var(--font-sans);
    font-weight: 600;
}

.footer-section ul {
    list-style: none;
}

.footer-section li {
    margin-bottom: var(--spacing-xs);
}

.footer-section a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.9rem;
    transition: var(--transition-smooth);
}

.footer-section a:hover {
    color: var(--accent-gold);
}

.footer-bottom {
    border-top: 1px solid rgba(212, 175, 55, 0.1);
    padding-top: var(--spacing-md);
    text-align: center;
}

.footer-copyright {
    color: var(--text-muted);
    font-size: 0.85rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    :root {
        --spacing-md: 1rem;
        --spacing-lg: 2rem;
        --spacing-xl: 3rem;
    }
    
    .nav-menu {
        display: none;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: var(--spacing-lg);
    }
    
    .title-main {
        font-size: 3rem;
    }
    
    .title-sub {
        font-size: 1.5rem;
    }
    
    .hero-actions {
        justify-content: center;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .learning-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .ai-feature {
        grid-template-columns: 1fr !important;
        text-align: center;
    }
    
    .ai-feature:nth-child(even) .ai-feature-visual {
        order: 0;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .footer-links {
        grid-template-columns: 1fr;
        gap: var(--spacing-md);
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .title-main {
        font-size: 2.5rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .hero-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .btn-primary, .btn-secondary {
        width: 200px;
    }
    
    .word-card {
        max-width: 280px;
    }
    
    .mind-map {
        width: 300px;
        height: 300px;
    }
} 